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Compare Generators Side-by-Side

Select up to 4 generators to compare specs, power output, noise levels, runtime and more. Your compare URL is shareable.

  • Firman WT05571
  • Cat RP6500 E
  • Model WT05571
    Model WT05571

    Firman 5,500W Tri-Fuel Generator

    5500W
    Running
    67 dB
    Noise
    View details
  • Model RP6500 E
    Model RP6500 E

    Cat 6,500W Gas Generator

    6500W
    Running
    0 dB
    Noise
    View details
Quick charts
Each chart uses its own Y-axis scale (so numbers are comparable within a chart).
Running watts
W
Starting watts
W
Noise
dB
Runtime @50%
h
Running watts by fuel
Shows how output changes across gasoline/propane/natural gas (when available).
Generator Specifications Comparison
SpecificationFirman WT05571Cat RP6500 E
General
Product type
Generator
Generator
Fuel
Tri-Fuel
Gasoline
InverterYesNo
Parallel capableYesNo
RV readyYesNo
Running watts
5500 W
Winner: Winner: 6500 W
Starting watts
6850 W
Winner: Winner: 8125 W
Noise (lower limit)
Winner: Winner: 67 dB
0 dB
Weight
Winner: Winner: 131.4 lbs
202 lbs
Run time @50% load
Not available—
Winner: Winner: 12 h
Run time @25% load
14.5 h
Not available—
Fuel tank
5.3 gal
7.9 gal
Fuel gaugeYesYes
Approx. dimensions (L × W × H)
27.6 x 21.3 x 22.6
32.9 x 27.4 x 24.7
Electrical
Voltage (AC)
120/240
120/240
Voltage (DC)
12
Not available—
GFCI outletsYesYes
Covered outletsYesYes
Automatic Voltage RegulationYesYes
THD
3 %
Not available—
Engine
Engine
322 cc OHV 4-stroke, cast iron sleeve.
420 cc OHV 4-stroke
Alternator
Not available—
Not available—
Starting system
Recoil, Electric
Recoil, Electric
Warranty
Warranty
3 years
2 years
Power by fuel
GasolineNot available—Not available—
Running watts
5500 W
6500 W
Starting watts
6850 W
8125 W
Running amps (120V)
Not available—
Not available—
Running amps (240V)
Not available—
Not available—
Peak amps (120V)
Not available—
Not available—
Peak amps (240V)
Not available—
Not available—
Run time @50% load
Not available—
12 h
Run time @25% load
14.5 h
Not available—
Natural gasNot available—Not available—
Running watts
4500 W
Not available—
Starting watts
5500 W
Not available—
Running amps (120V)
Not available—
Not available—
Running amps (240V)
Not available—
Not available—
Peak amps (120V)
Not available—
Not available—
Peak amps (240V)
Not available—
Not available—
Run time @50% load
Not available—
Not available—
Run time @25% load
Not available—
Not available—
PropaneNot available—Not available—
Running watts
5000 W
Not available—
Starting watts
6250 W
Not available—
Running amps (120V)
Not available—
Not available—
Running amps (240V)
Not available—
Not available—
Peak amps (120V)
Not available—
Not available—
Peak amps (240V)
Not available—
Not available—
Run time @50% load
Not available—
Not available—
Run time @25% load
9.5 h
Not available—
Other
Data center
Not available—
Not available—
Indicators
Not available—
false
Compliance
EPA, ANSI/PGMA G300-2023
CARB, EPA
Security
Not available—
Not available—
Spark arrestorYesYes
Neutral
Bonded to frame
true
UPC
840876155714
815683020067
Core / High-priority specs
Running Watts (Gasoline)
5500
6500
Running Watts (Propane)
5000
Not available—
Running Watts (Natural Gas)
4500
Not available—
Starting Watts (Gasoline)
6850
8125
Starting Watts (Propane)
6250
Not available—
Starting Watts (Natural Gas)
5500
Not available—
Runtime @ 50% Load (Gasoline)
Not available—
12
Runtime @ 25% Load (Gasoline)
14.5
Not available—
Runtime @ 25% Load (Propane)
9.5
Not available—
AC Outlet Types
1x Duplex 120V 20A (5-20R) GFCI; 1x 120V 30A (TT-30R); 1x 120/240V 30A (L14-30R); 1x 120/240V 50A (14-50R)
2x Duplex 120V 20A (5-20R); 1x 120/240V 30A (L14-30R); 1x 120V 30A (L5-30R)
Electrical & power
Frequency
60
60
Engine & construction
Engine Type
OHV 4-stroke
OHV 4-stroke
Engine Displacement
322
420
Cylinder Sleeve
cast iron sleeve
Not available—
Engine Oil Type
Not available—
SAE 30 or 10W-30
Runtime & fuel system
Runtime @ 25% Load (Gasoline)
14.5
Not available—
Runtime @ 50% Load (Gasoline)
Not available—
12
Safety & compliance
Overload Protection System
Low oil and overload protection, CO monitoring
Low oil and overload protection
Low Oil ProtectionYesYes
Carbon Monoxide MonitoringYesNo
Included equipment
Starting Components
Oil, funnel, tool kit, propane hose, and battery
Recoil, Electric
Included Accessories
Oil, funnel, tool kit, propane hose, and battery
Oil, funnel, tool kit, battery, and wheel kit
Warranty & identification
Commercial Warranty
3
Not available—
Part Number
Not available—
502-3688
Additional specs
Summary
The Firman WT05571 is a 5,500-watt tri-fuel generator that runs on gasoline, propane, or natural gas. On gasoline, it delivers 6,850 starting watts and 5,500 running watts, enough to power a full home electrical panel during an outage or run multiple job site tools simultaneously. On propane, output drops to 6,250 starting and 5,000 running watts. On natural gas, it falls to 5,500 starting and 4,500 running watts. This fuel flexibility means users can switch between sources based on availability, cost, or storage preference without buying multiple generators. The tri-fuel capability makes this unit valuable for homeowners in regions with natural gas infrastructure, RV owners who can refill propane at any campground, and contractors who need to adapt to job site fuel availability. The 3 percent THD rating protects laptops, televisions, and other sensitive electronics from voltage spikes that damage circuits. At 67 decibels, the noise level sits between a typical conversation and heavy traffic, making it suitable for residential neighborhoods but audible enough that neighbors will know it is running.
The Cat RP6500 E is a 6500-watt gasoline generator built for residential backup and light commercial work. Its 8125-watt peak capacity means it can start large tools and appliances that draw high inrush current, then sustain 6500 watts of continuous power for multiple devices simultaneously. A 7.9-gallon fuel tank delivers 12 hours of runtime at 50% load, which translates to roughly one full workday or overnight backup without refueling. The gasoline engine is straightforward to maintain and refuel anywhere, making this unit practical for job sites, outdoor events, and emergency home power.
  • Most Powerful
    Cat RP6500 E
    6500W running
  • Quietest
    Firman WT05571
    67 dB
  • Longest Runtime
    Cat RP6500 E
    12h at 50% load
Where to buy
Prices can change. We update these automatically.
Firman WT05571
Store links
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Cat RP6500 E
Store links
No links yet.
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